POSIX Overlay Filesystem (posixovl)

A FUSE (filesystem in userspace) filesystem that provides POSIX functionality -
UNIX-style permissions, ownership, special files - for filesystems that do not
have such, e.g. vfat. It is a modern equivalent of the UMSDOS fs.

It provides a filesystem view that supports various POSIX operations while using
an otherwise incapable lower filesystem. Filesystems of various degrees of
POSIXness can be utilitzed. VFAT is a common  denominator  when it comes to
cross-compatibility, though NTFS — its features are unused in Linux — would be
another possibility. Secondly, potent native POSIX-style filesystems can also
be used, though the actual use of doing that remains to be discovered.
